#!/usr/bin/env python3
# Copyright 2019 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

from __future__ import division
from __future__ import print_function

import argparse
import json
import logging
import os
import sys
import tempfile
import time


sys.path.insert(
  1,
  os.path.join(
    os.path.dirname(__file__),
    os.pardir,
    os.pardir,
    os.pardir,
    os.pardir,
    'third_party',
    'catapult',
    'tracing',
  ),
)
from tracing.metrics import metric_runner
from tracing.metrics import discover
from tracing.value import histograms_to_csv


def main():
  all_metrics = discover.DiscoverMetrics(['/tracing/metrics/all_metrics.html'])

  parser = argparse.ArgumentParser(description='Runs metrics on a local trace')
  parser.add_argument(
    '--local-trace-path', type=str, help='The local path to the trace file'
  )
  parser.add_argument(
    '--cloud-trace-link',
    type=str,
    help=('Cloud link from where the local trace file was downloaded from'),
  )
  parser.add_argument(
    '--metric-name',
    type=str,
    help=(
      'Function name of registered metric '
      '(not filename.) Available metrics are: %s' % ', '.join(all_metrics)
    ),
  )
  parser.add_argument(
    '--output-csv', default='results', type=str, help='Output CSV file path'
  )

  args = parser.parse_args()

  trace_size_in_mib = os.path.getsize(args.local_trace_path) / (2**20)
  # Bails out on trace that are too big. See crbug.com/812631 for more details.
  if trace_size_in_mib > 400:
    print('Trace size is too big: %s MiB' % trace_size_in_mib)
    return 1

  logging.warning('Starting to compute metrics on trace')
  start = time.time()
  mre_result = metric_runner.RunMetric(
    args.local_trace_path,
    [args.metric_name],
    {},
    report_progress=False,
    canonical_url=args.cloud_trace_link,
  )
  logging.warning(
    'Processing resulting traces took %.3f seconds' % (time.time() - start)
  )

  for f in mre_result.failures:
    print('Running metric failed:')
    print(f.stack)
    return 1

  with tempfile.NamedTemporaryFile(mode='w') as temp:
    json.dump(
      mre_result.pairs.get('histograms', []),
      temp,
      indent=2,
      sort_keys=True,
      separators=(',', ': '),
    )
    temp.flush()

    result = histograms_to_csv.HistogramsToCsv(temp.name)
    if result.returncode != 0:
      print('histograms_to_csv.HistogramsToCsv returned %d' % result.returncode)
      return result.returncode
    with open(args.output_csv, 'wb') as f:
      f.write(result.stdout.rstrip())
    print('Output CSV created in file://' + args.output_csv)


if __name__ == '__main__':
  sys.exit(main())